Current treatment for atherosclerosis involves lipid-lowering medications and drugs that affect lipid metabolism, including statins, bile acid absorption inhibitors, cholesterol absorption inhibitors, fibrates and antioxidants such as probucol, among others. (Zipes et al. Eds., 2005, Braunwald's Heart Disease, Elsevier Saunders, Philadelphia). These treatment regimens are based, at least in part, on the theory that oxidized lipoproteins are the main causative factor of atherosclerosis. However, the exact mechanism by which cholesterol oxidizes is still not fully understood.
Archaea are the most ancient microorganisms existing in nature, but have been characterized only recently. See, Woese et al., Proc Natl. Acad. Sci. U.S.A. 74: 5088-5090 (1977). They inhabit extreme environments and are constituted by lipid monolayer membranes. Rich alkaline atmosphere with sodium ions and metals prevents proliferation of other bacteria, but is favorable to archaea's growth. Archaea have been isolated from alkaline waters from the Dead Sea, the Great Salt Lake and Yellowstone National Park. They have a small size, can—just barely—be viewed with an optical microscope, and observation of structural details requires electron microscopy. See, Howland et al., The surprising archaea. Discovering another domain of life, Oxford University Press (New York, 2000). Some are considered hyperthermophilic as they survive in very high temperatures.
Another unusual characteristic of some archaea is that they appear to use metal as an energy source. See, Amend et al., F.E.M.S. Microbiol. Rev. 25: 175-243 (2001). It is considered that archaea usually need an anaerobic or nearly anaerobic environments to carry out oxidation-reduction reactions with participation of different chemical compounds, including metals.
Recently, a new kind of extremely small archaea, which is dependent on bigger archaea, was described and named nanoarchaea. See, Huber J et al., Nature 417: 63-67 (2002). With the exception of archaea that reside in the mammalian intestine and produce methane gases, there is no report of archaea existing within plants or animals. See, Florin T H J et al., Am. J. Gastroenterol. 95: 2872-2879 (2000).